Fair Value Measurements - Additional Information (Detail) - USD ($) $ in Millions	3 Months Ended		12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2014		Dec. 31, 2013	[2]	Dec. 31, 2015
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Estimated fair values of debt instruments	$ 7,900		$ 7,900				$ 16,500
Outstanding principal amount of debt instruments	7,041		7,041				16,296
Unamortized discount on long-term debt	872		872				$ 941
Goodwill impairment charge	$ 119	$ 195	$ 119	[1],[2]	$ 195

[1] The impairment in 2014 relates to our Technical Services reporting unit within our IS&GS business segment (Note 1).

[2] We recognized non-cash goodwill impairment charges related to the Technical Services reporting unit within our MFC business segment in 2014 and 2013. See Note 1 for more information.